Rotary piston and cylinder construction



LiS TER 1,972,?44

ROTARY PISTON AND CYLINDER CONSTRUCTION Sept 4, Original Filed Jan. 11,1923 4 Sheets-Sheet l Sept. 4, 1934. w. LISTER ROTARY PISTON ANDCYLINDER CONSTRUCTION Original Filed Jan. 11, 1923 4 Sheets-Sheet 2Sept. 4, 1934. w LISTER 1,972,744

' Original Filed Jan. 11, 1923 4 Sheets Sheet 5 Sept; 4, 1934. w. LISTERROTARY PISTON AND CYLINDER'CONSTRUCTION 11, 1923 4 SheetsSheet 4Original Filed J cm.

Patented Sept. 4, 1934 UNITED STATES PATENT OFFHQE ROTARY PISTUN ANDCYLINDER CONSTRUCTION Renewed February 8, 1934 6 Claims.

My invention is concerned with rotary piston and cylinder constructiondesigned primarily for steam engines, but which can be used for rotarypumps, compressors, etc., and is intended to produce a device of theclass described that will be highly efilcient and prevent any possibleloss of pressure in the device due to leakage.

To illustrate my invention, I annex hereto four sheets of drawings, inwhich the same reference characters are used to designate identicalparts in all the figures, of which,-

Fig. 1 is a central vertical section through an engine embodying myinvention;

Fig. 2 is a section on the line 22 of Fig. 1;

Fig. 7 is a central vertical sectionillustrating a portion of themechanism seen in Fig. 2, but with the blade in a different position;

Fig. 8 isa section on the line 8-8 of Fig. '7; i

25 and Fig. 9 is a detail in perspective illustrating some of the partsseparated.

The complete cylinder is preferably made up of the outer cylindricalcasing ring closed by the end plates 33 and having secured therein theinner cylindrical ring 25, as hereinafter described. The casing ispreferably constructed of the central casting 20, generally annular inshape, and having the inlet aperture 21 and the outlet aperture 22located in suitable sleeve-like extensions from the main cylindricalbody. A third extension or lug 23 is internally threaded and receivesthe set screw 24 which engages the ring 25, fitting closely inside ofthe ring 20, of the same width, and having its inner surface eccentricto the ring 20 and also to its own outer surface. This inner surface ismade up substantially of four parts, the smaller section 26 being formedon a circular curveconcentric with the ring 20, and it is opposed byasurface 27 likewise circular and concentric, while the two surfaces 26and 27 are connected by the surfaces 28 and 29, which are curved, but ondifferent centers from the surfaces 26 and 27. The design of these foursurfaces is such that the effective diameter of the eccentric internalsurface thus produced is the same in any position of the blade or bladeswhose ends co-operate therewith. The ring has the inlets 30 and 31registering with. the inlets 22 and 21 tion, and composed of springmetal. I understood of course that the function of these and arepreferably threaded, as seen at 32, so that a nozzle of any desireddesign can be screwed into either of them, depending on which way it isdesiredv to have the engine rotated.

I preferably, especially for the largerunits, install either a Corlissor a poppet valve on the inlet port for the purpose of cutting off thesteam to get fuller expansion. The open cylinder thus formed is closedat its ends by the end plates 33, symmetrical in design, and which havethe flanges 34 overlapping the outer edges of the ring 20, to which theyare secured by the screws 35, as will be readily apparent. The centralportions of the end plates have the bosses 36 which form bearings forthe shaft 3'7, and on 7 the inner faces of the ends are the circularrecesses 38, which are concentric with the shaft 3'7, and are of thesame radius as the portion 26 of the surface of the ring 25.

The shaft 37 is preferably provided with the 7 enlarged central portion39, through which passes the rectangular opening 40 to accommodate theblade or blades 41v therethrough. The rotor is made up of the enlargedcentral portion of this shaft 37, and the semicylindrical halves 30 42,which have the central portion of full diameter, with the reducedportions 43 of somewhat smaller diameter, and the reduced portions 44 ofstillsmaller diameter forming seats for the rings 45, best seen in Fig.3, which are secured by the screws 46 to the ends of therotor sections,thus forming at each end an annular channel adapted to receive theexpanding rings 47, made up of two sections 47 and 47*, as described atlength further on inthe specifica- It will be rings 47 isto form apacking and prevent the escape of the steam past them and out thebearings of the shaft 3'7. The two halves 4.2 of the rotor are securedtogether by the screws 49, as clearly shown in Fig. 3, and the dowelpins 50 may be employed for positioning the rings 45 before the screws46ers driven. I preferably pin the rotor to the shaft 37 by the pins 51,1 seen in Figs. 2 and 3.

As the piston blade slides through the center of the rotor with its endsco-operating with the eccentric inner periphery of the ring 28, it willbe obvious that to co-operate therewith perfectly,

the ends at least of the piston blade must be capable of some relativemovement to make the desired perfect contact, and that as a result thepiston blade must be compound, and not merely a simple integral blade.

The blades 41 may take various forms, but I prefer to employ a pair ofsaid blades, and provide each blade with a sliding contact rib 52mounted to slide in recesses formed in the ends of the blades 41 andpressed outward by the springs 53 set in pockets 54 in the bottoms ofthe recesses in the blades accommodating the ribs 52. This constructionensures steam-tight engagement of the ends of the blades with thesurfaces 26, 27, 28 and 29, and it will be noted from the dotted-lineposition shown in Fig. 1 that the two ribs 52 can occupy difierentpositions to make a double engagement with said surfaces in allpositions of the blades. It is desirable to have the ends of the bladespressed in steam-tight engagement with the ends of the channel 40through the enlarged portion of the shaft and with the correspondingoffsets 55 of the rotor sections 42, with which offsets the ends of theblades engage, and, for this purpose, I form the blades 41 in twosections 41 and 41*, as best seen inFig- 2, and themeeting edges ofthese sections are provided with intermeshing rectangular teeth 56,so'that the two sections of the blades can be thrust toward theends ofthe engine under the impulse of the helicallycoiled expanding springs5'7 set in the recesses 58 formed in the sections of the blades, asclearly shown in Fig. 2. It is desirable, of course, that the contactribs 52 also have their ends pressed against the offset portions 55 andthe surfaces 59 of theend plates, and to obviate the necessity ofemploying springs for these ribs, which are also divided into sections52 and 52*, as seen in Fig. 2, like thesections of of the blade proper,I provide in the ribs the radially-extending channels 60, which areengaged by the ribs 61 formed on the inner surfaces of the recesses inthe ends of the blades 41, as seen in Fig. 6. By this means, it will beobvious that the contact ribs 52 will have their ends moving with theends of the blades 41 to ensure the desired steam-tight contact.

It is also desirable to provide means for preventing the escape of thesteam from one side of the piston to the other between the adjacentsurfaces of the pairs of blades 41, and for this purpose I employ theconstruction shown in Fig. 6 where the sections 42 are provided neartheir ends with the rectangular recesses 62,

which recesses are tapered in depth, as shown in Fig. 6, and receive intheir bottom the tapered plate or key 63, which is pressed against thecontact bar 64 overlying it by the helicallycoiled expanding spring 65located in the end of the recess and held to its work by the'screw 66threaded into the portions of the rotor 42 directly-beneath the offsets43 thereof. With the construction shown, it will be obvious that thepressure of the spring 65 acts throughthe keys 63 and bars 64 to pressthe two blades 41 into engagement so as to prevent the passage of steambetween them.

' In Figs. 7, 8 and 9, I have illustrated in detail the packing rings 47and 47 whosediameters are made adjustable to secure more efficientaction. The ring is made in two sections, 47

and-47 with their adjacent surfaces tapered,

shifting, I provide them with the lugs 47 and 47 which fit into thecorrespondinglyshaped recesses 45 formed in the inner faces of the rings45 If the ring 47 becomes worn so as to permit some leakage, by turningthe screws 46 it can be expanded so as to take up the wear and secure astight a joint as is desirable.

The set screw 24 is screwed down as tightly as may be desired, and itwill be understood that the tighter it is screwed down, the more closelythe section 26 of the inner periphery of the annulus 20 engages therotor, thus enabling me to prevent any possibility of steam leaking bythe section 26 to the exhaust side due to its pressure.

The structure and purposes of the various features having been thusdescribed, the mode of operation of the apparatus will be readilyapparent without further explanation.

While I have shown and described my inven tion as embodied in the formwhich I at present consider best adapted to carry out its purposes, itwill be understood that it is capable of modifications, and that I donot desire to be limited in the interpretation of the following claimsexcept as may be necessitated by the state of the prior art.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is:

1. In a device of the class described, the'combination with a cylinderhaving inlet and outlet ports and the eccentric interior portion withthe concentric end portions of smaller diameter, of a rotormountedconcentrically in the cylin- 'der, a blade sliding radiallythrough the rotor and engaging the eccentric interior ofthecylinder'with its ends, expanding rings mounted in annular grooves inthe rotor within the smaller portions of the cylinder and engaging saidsmaller portions for the purpose described, and means for the adjustingthe peripheral diameter of the expanding rings to take up wear, saidmeans consisting of transversely beveled rings within the expandingrings, and me'chanismfor forcing said beveled ringstoward the center andholding them in the positions to which they are moved. 1 V

2. In a device of the class described, the combination with a cylinderhaving inlet and outlet ports and the eccentric inner portion with theconcentric end portions of smaller diameter, of a rotormountedconcentrically in the cylinder, a blade sliding radially throughthe rotor and engaging the eccentric interior of the cylinder with itsends, expanding rings mounted on reduced annular portions of the rotorwithin the smaller portions of the cylinder and engaging said portionsfor'the purpose described, transv ersely beveled rings within theexpanding rings, retaining ring also upon the still more reduced annularportions'of the cylinder to hold the expanding and beveled ringsinplace, and screws cooperating with the retaining rings for forcingthem toward the center. Y

' 3. Ina device of the class described, the combination with a cylinderhaving inlet and'outlet ports, of a rotor journaled thereineceentrically of the bore of the cylinder, a compound piston ist its

blade sliding/through the centerj of the rotor,

packing bars 'in the rotor engaging the faces of the blade, taperingpressure bars mounted to slide in the rotor longitudinally of the axisthereof and engage the packing bars, the-engaging faces 'of the rotor.being. correspondingly tapered, and springs in the rotor to engage theends of the pressure bars and thereby press the packing bars against thefaces of the blade with substantially unvarying pressure.

4. In a device of the class described, the combination with a cylinderhaving inlet and outlet ports and the eccentrically located bore orinterior portion with the concentrically located end portions of smallerdiameter, of a rotor mounted concentrically in the cylinder with itsends extending into said smaller end portions, a compound blade slidingradially through the rotor and engaging the eccentric interior of thecylinder with its ends, and expanding rings mounted in annular groovesin the rotor within the smaller portions of the cylinder and engagingsaid smaller portions for the purpose described, the single opening ofeach of said expanding rings being in line with the radial space coveredby the adjacent end of the blade.

5. In a device of the class described, the combination with a cylinderhaving inlet and outlet ports and the eccentrically located bore orinterior portion with the concentrically located end portions of smallerdiameter, of a rotor mounted concentrically in the cylinder with itsends extending into said smaller end portions, a compound blade slidingradially through the rotor and engaging the eccentric interior of thecylinder with its ends, expanding rings mounted in annular grooves inthe rotor within the smaller portions of the cylinder and engaging saidsmaller portions for the purpose described, the single opening in eachof said expanding rings being in line with the radial space covered bythe adjacent end of the blade, and retaining rings secured upon thestill more reduced annular portions of the rotor to hold said rings inplace.

6. In a device of the class described, the combination with a cylinderhaving inlet and outlet ports, of a rotor journalled thereineccentrically of the bore of the cylinder, a compound piston bladesliding through the center of the rotor, packing bars in the rotorengaging the faces of the blade, pressure bars mounted to slide in therotor longitudinally of the axis thereof and engage the packing bars totake up automatically the wear thereon, and springs in the rotor toengage the pressure bars and thereby press the packing bars against thefaces of the blade with substantially unvarying pressure.

WILLIAM LISTER.

